John Lydon's Stepdaughter Ari Up Died Due to 'Serious Illness'

Ari Up aka Arianna who is also the frontman of The Slits passed away at the age of 48 on Wednesday, October 20.

The Slits frontwoman Ari Up has died at the age of 48. The punk pioneer passed away on Wednesday, October 20 after suffering a "serious illness", according to her stepfather, Sex Pistols rocker John Lydon.

No further details of her cause of death were given as WENN went to press. Lydon, who is married to Up's mother Nora, confirmed the sad news in a post on his official website. The message reads, "John and Nora have asked us to let everyone know that Nora's daughter Arianna (aka Ari-Up) died today after a serious illness. She will be sadly missed. Everyone at JohnLydon.com and PiLofficial.Com would like to pass on their heartfelt condolences to John, Nora and family. Rest in peace."

The singer, who was born Arianna Forster, formed the British rock band in 1976 when she was just 14 years old and they went on to release three albums and tour with The Clash before disbanding in 1982. Up later worked on solo projects and notably joined collaborative music group the New Age Steppers before she reunited the band with new members in 2005. They continued to release new music and tour up until this summer when the band cancelled an appearance at Britain's The Great Escape music festival without giving a reason.